pub fn migrate<A, S, Q, M, U>(
instance: &mut Instance<A, S, Q>,
env: Env,
msg: M,
) -> ContractResult<Response<U>>where
A: BackendApi + 'static,
S: Storage + 'static,
Q: Querier + 'static,
M: Serialize,
U: DeserializeOwned + CustomMsg,